The invention relates to a liquid-cooled electric generator for a motor vehicle, especially for a motor cycle, bus, train or the like.
An electric generator of this type is known, comprising a rotor with a rotor shaft, a stator, a housing which has bearings for the rotor shaft and in which the stator and the rotor are mounted and a liquid cooling device and having a cooling jacket for cooling liquid.
The liquid cooling of electric, to be precise highly loaded, generators, in particular in the field of motor vehicles. Various types of cooling are used in these electric generators including manifold cooling, so-called jacket cooling, spray-oil cooling or in the form of direct conductor cooling. A list of possible types of ventilation for electric machines can be found in the book "Elektrische Maschinen" [Electric Machines], vol 1, Richter, Birkhauser-Verlag, 1967, pages 295-307. It is also known in an oil-cooled generator (German Patent 3,038,444) to mount the field winding on the internal pole of the generator with the aid of a winding support and to construct the winding support on its bore surrounding the internal pole with ribs in order to form ducts guiding a cooling oil flow between the winding support and the internal pole.
In a further known liquid-cooled heating generator (German Offenlegungsschrift 3,129,817), the stator of a heating generator operating according to the induction principle, in particular for heavy goods vehicles, has a plurality of armature bars which are arranged distributed in the circumferential direction, are connected by short-circuiting rings on both sides of the stator lamination, and through which a liquid heat carrier flows.
It is also known to use the dissipated power of a motor vehicle generator for heating purposes (German Offenlegungsschrift 3,128,081), there being provided in the region of the stator and the bearing brackets cooling ducts for a liquid, which form a cooling jacket and are connected to the coolant circuit of the motor vehicle driving the generator. In this case, an additional heating generator can also be driven by the same shaft of the motor vehicle generator.
A similar solution is described in German Offenlegungsschrift 3,207,605. In this apparatus a cooling air circulation which sweeps over the winding and the rotor is maintained in the housing of the generator and a part of the housing forms heat-exchanging elements around which the cooling air circulation flows. The heat exchanging elements have an inlet and an outlet for a cooling liquid circuit located outside the bearing housing.
Finally, it is known (German Offenlegungsschrift 3,135,901), in a three-phase generator to connect lubricating oil ducts to the two antifriction bearings of the rotor shaft, the rotor shaft containing a central longitudinal bore which in the vicinity of the drive-side antifriction bearing merges into at least one radial bore which opens into an annular space suitable for receiving lubricating oil. In this case, means are provided to simplify such an oil lubrication by connection to the lubricating oil circuit of an internal combustion engine, the oil discharge taking place via the drive-side bearing cover of the three-phase generator.